Door alarm apparatus of the propped-against type have been developed in the past. These apparatus are intended to be set up in front of a door, once the door has been closed, and have the feature that they are intended only for temporary installation, when the door is closed and not in use. This invention relates to such door alarm apparatus and more specifically to those apparatus adapted to hold or otherwise activate a handgun shaped alarm member.
Such apparatus in the past have taken principally two formats. The first is an apparatus wherein the activating member is jammed against the door and frictionally held in position with respect to the floor surface behind the door. Such frictional holding has been assured by usually a large frictional surface area of the apparatus in contact with the floor, or, alternately, has been assured by a wedging member digging into or otherwise scraping along the floor mounting ever increasing resistance as the door is opened thereagainst.
The second format includes the fixed mounting of the apparatus to the wall immediately adjacent the door.
These prior art teachings exhibit certain shortcomings which this invention hopes to overcome. Particularly, those which are permanently mounted to the wall area adjacent the door are undesirable as they are not readily removable when the door is in use. Those which wedge or frictionally act against with the floor are also undesirable as they may easily be knocked over or dislodged from their intended position by a child or pet who brushes against them. Moreover, they provide no precise fixed reference point with respect to the closed position of the door. Such latter type devices may be wedged tightly against the door in a first installation and not so tightly against the door in a second installation. Moreover, for those of this type which are propped or lean against the door the angle at which they are leaned against the door may vary from use to use.
It is important to develop such an easily removable alarm apparatus which is easily installed to a predetermined and fixed spatial frame of reference with respect to the closed door. This enables a precise adjustment of the trigger mechanism which assures uniform operation not generally available with prior devices. It is also desirable to provide such an apparatus with a secured anchorage which will prohibit the apparatus from being dislodged from its operational position by the movements of a child or a pet.
An object of this invention is to provide a threshold plate door alarm which alarm may be securely attached to the threshold plate in a predetermined and fixed spatial association with the closed door.
A second object of this invention is to provide such an apparatus which may be securely anchored in such predetermined position.
A third object of this invention is to provide such an apparatus which is easily removable from its installed position.
A further object of this invention is to provide an activator and carriage for communicating with and operating a handgunlike shaped audible alarm member.